Stop mechanism



Dec. 2, 1924.

L. E. TQPHAM STOP MECHNISM Filed July 12, 1917 3 Sheets-'Sheet 1 Dec, 2, 1924.

I...4 E. TCPHAM- STOP MECHANISM Filed July 12. 1917 s sheets-sheet @SEE Dec. 2, 1924. 1,517,872

n.. E. roPHAM STO? MECHANISM Filed July 12. 1917 3 Sheets-Sheet 25 LAURENCE E. TOHAM, OE S/VAMFSCTT. 'MASSAGHUSF'TT ASSIGNOB, BY DIESNE ASSIGNMENTS, TG UNITE-3" {S-10E vAC-INERY CORGRATION, 0F PATER-SON, NEW' JERSEY, A CORPORATION G1? NEVI' JERSEY.

STOP MECHANISM.

Application filed E. Torlt is the object of the invention to provide a novel and improved mecl'ianism which will operate efficiently and uniformly in stopping the driven parts of machines the speed of which may vary at the time the mechanism comes into action.

To this end the invention contemplates the provision of speed reducing means acting to gradually retard the driven parts before they reach their :final stopping position. the

retardinsr effect of which` is controlled bv the speed of such parts at the time the stopping is to be effected, the retarding effect being increased hy increasing the intensity or the duration with relation to the movenient of the partsof the action ofthe retarding means with an increase in the speed` and heine; reduced by reducing the intensity or duration of the action ofv the retarding means, with a reduction in the speed. The retarding action is thus controlled to secure a `gradual slowing down of the driven parts as they come to stopping position, whatever their speerL at the time the stopping is to be effected. t is preferred to employ a friction brake as the means for retardingorretarding and stopping' the driven parts7 and to vary its retarding effect by varying` the period er interval in the movement of the parts of its activity in accordance witli the speed, although this construction and specific mode of operation is not essential to the broader features of the invention. rl`he period during which the retardation or slowing down ofthe driven parts continues is preferably controlled by cam, the position and timing of whi-ch with relation to the movement of the parts is varied loy a centrifugal v governor, and this construction constitutes July l2,

1er?. serial No. 180,115.

a feature of the invention which not confined 1n its application to mechanisms 1n which a retarding means is applied when or ,slowing down the machine when theY power is thrown off.

The various features of the invention will be readily understood from an inspection of the accompanying drawings and the following detailed description of the mechanism` illustrated therein.

1n the drawings, Figure 1 is a side elevation showing a'meehanism embodying the invention in its preferred form; Fig. 2 is a sectional detail through the axis of the stud which supports the clutch operating lever and other parts of the mechanism; Fig. 3 is a sectional elevation on line 3, Fig. 1; 4t is a sectional view on line 4, Fig. 8; and Fig. 5 is a view similar to Fig. 3, showing the parts in a different position.

In the drawings the invention is shown embodied in a mechanism for driving and stopping a shaft 2 from which the operatingr mechanisms of a sewing or other machine may be driven. rihe mechanism for driving the shaft during the operation of the machine comprises a wheel le which is secured to the fiange of a sleeve 6 which is in turn secured to the shaft. The wheel is provided with a clutch face 8 arranged to be engaged by a clutch face 10 on a constantly rotating driving pulley l2 which is loosely mounted on the sleeve 6. The pulley 12 may be moved on the sleeve toengage or disengage vthe clutch face, or to vary the speed of the driven shaft, through a clutch operating arm 14, the upper end of which is provided with a cam face 16 engaging a bearing block 18 on the pulley, and the lower end of which is secured to the hub 2O of a lever 22. rlhe end of the lever 22 may be connected through a rod 24: with an operating treadle (not shown), through which the operator may control the engagement and disengagement of the driving clutch member and the operation of the stopping mechanism. The clutch operating lever 22 is held kin clutch disengaging position by a spring 26 which normally holds the stop screw 28 on the lever in engagement with a stop lug` El) on a fixed bracket 32.

The mechanism shown 'tor retardinja` and stopping the shaft 2 when the drivingl clutch is disengaged by the release ot the lever 22 comprises a brake shoe arranged to engage the rim ot the Wheel at, and a stop dog: 3G movable into and out ot the path ot Va stop lug)r 38 secured to the ivhee. The brake shoe .nd stop dog" are secured on an arm il() which is pivotally supported upon a stud l2 upon Which the clutch operating' lever 22 is also mounted. 'lhe arm 40 is normally supported in position "with 'the brake snoe out ot engagement with the Wheel l and the stop dog 88 out ot the path ot the stop lug` 887 as indicated in F@ 5, by a stop screw stil carried by the bracket 32 and arranged to engage a lng' i8 on the upper end ot the arm. The means for ap plyinkaj the brake and bringing` the stop dog-r into active position when the power is thrown ott by the release ot the lever comprises a lever i8 loosely mounted on the hub ot the arm 40, and a latch link 507 one end ot which is pivoted to the upper end ot the arm 40, and the other end ot which is provided with a hook 52 adapted to en- ,gage a shoulder 541 on the lever. The link is drawn in a direction to engage its hook end with the shoulder on the lever 48 by a spring` 58 Which connects the link with a pin on the bracket 82. The upper end ot the lever e8 is arranged to be engaged by a cam 58 carried on the shaft Qi and operating;` to apply the brake and render the stop don` active When in engagement With the upper end of the lever. lVhen the driving` clutch is engaged., the latch link 5() is disenaagged trom the lever 48 and the lever is held out ot the path of the cam 58 by. a block 60 adjustably secured to the upper end ot an arm 'formed on the clutch oiwratina` lever 22., The latch link is held in its raised disengaged position by engagement with the upper end et the bloclnas indicated in ""1: 5. llllhen the lever 2:2 is released to disengag'e the driving` clutch` it savings into the position indicated in Fig. 8, and the arm 82 moves to the right in 3 and thus releasing); the latch link 50 and permitting the lever 48 to move toward the shaitt 2 under the intluence ot' the spring' 6l. 'lhe latch link rides on the shoulder 54st on the lever 48 until the shoulder passes to the right ot' the hook 52 'on the link, When the hook passes down to the lett otl the shoulder and into position to connect the lever with the arm 40. lrlovv when the cam dnring the rotation ot the shaft f acts upon the lever 48, the movement ot' the lever to the lett operates the arm 40 to apply the brake shoe Bel to the Wheel 4h and Vto brine' the stop dog 36 into the path of the stopv Leraar/a lug 387 so that the movement ot the shot-: is gradually retarded, and the shatt tinab ly brought to rest with the lug 88 in en ,sagement with the stop dog, as indicated in Fig. Pi. lll/when the lever 22 is depressed to again engage the driving` clutch, a rain surface on the block 60 acts to litt the lat/fh link 50, thns disconnecting the arm 4l() 'troni the lever d8, so that the brake shoe and stop dog` are ifree to return to their inactive position. The block G0 also engages the lever t8 and moves it out of the path ot the cani 58, as indicated in Fig.

ln order that the braking; e'tlect ot the brake shoe 34A may vary in accordance with the speed oit' the shaft 2 at the time ivlx/ 'the drivingf clutch is disengaged, the cam 58 is so mounted on the shatt 2 that its position circumterentially ot the shaft7 and thereiore the timing ot its action on the brake applying lever 48, may be varied in accordance With the speed ot the shait. ln the construction shown, the cam 58 is pivot ally mounted on a sleeve 66 which is in tarn mounted on the sleeve 6. rlhe cam is provided on its inner edge with a paivl @e arranged to engage ratchet teeth 70 torinfrl on the sleeve 6. rlhe position of the slet-vc G6 and ot the cam 58 on the shait Q is determined by tivo centrifugal governor arins F2 pivoted on the Wheel 4t and provided with gear segments 74 engaging a gear '(8 formed on the sleeve 66. T he governor arms are acted upon by springs 78 which tend to hold them substantially in the position indicated in Fig. 3.

When the shaft 2l is beingI drivenl the 3am 58 will be thrown into the position indicated in Fig'. 5 by centrifugal actioin its outward swinging' movement being` determined by the engagement otvits torivard end with a stop surtace on the sleeve (it. The sleeve and cam are therefore tree to be moved about the shatt in either direction by the swinging` movement ot the centritngovernor arms 79a lWhen the shat't being driven at slow speed the governor ai and the cam 58 will occupy substantialfy the position indicated in Fig. 8, and the shaft Will come into stopping' position shortly after the cam has acted to apply the brake. lt the shaft is being` driven at hi gli speed when the clutch lever 22 is released to disconnect the power, the centrituaal governor arms and the cam 58 will occupy substantially the position indicated in Fini. when the cam 58 engages the brake plyinov lever 4l8 and the brake Will be applied and held in braking` engagement With the Wheel 4 tor a comparatively lone` interval betore the parts come to stopping; position. The extent to which the governor arms advance the cam on the shaft 2, and consequently the period during; which the brake is applied before the parts come to Leraars stoppingr position will depend upon the speed at which the shaft is rotating when the stop mechanism is thrown into action by the release of the clutch shifting lever 22. rlhe position of the cam on the shaft 2 determined by the engagement of the paivl 68 on the cam With the ratchet teeth TO When the cam engages the lever e8, the cam being locked in position on the shaft by the paivl and ratchet teeth during the subsequent revolution ofthe shaft, and While it is being slowed down and stopped by the retarding and stopping devices.

l'y the above mechanism the retarding effect of the brake is varied in accordance with the speed of the shaft 2 and the parts driven therefrom at the time the stopping is to be effected, so that the parts Will be uniformly brought to rest in a predetermined position Without regard to the speed at the time the retarding and stopping mechanism comes into action. The parts may be so designed and adjusted that the shaft Will be brought to rest by the brake at a uniform point in its rotation, but it is preferred to provide stopping devices such as the stop dogg- 36 and lug` 38 which come into engagement and determine the final stopping position, since with this construction any slight variation in the stopping position, d ue to variations in the action of the brake, may be avoided. ln the latter case the brake so retards the shaft prior to the engagement of the stopping devices that they eifect the final stopping Without undue shock or strain on the parts, the increased braking interval when stopping at high speed serving to .overcome the increased momentum of the part-s, so that the engagement of the stopping devices occurs under substantially uniform conditions.

The mode of operation of the mechanisms shown is briefly as follows: During the driving the lever 22 is depressed and the parts are substantially in the position shown in Figure lVhen the shaft 2 is to be stopped, the lever 22 is released and is raised by its spring into the position indicated in Figure 3. By this movement the block. 6() is carried to the ri glit, permitting the lever 48 to move into the path of the cam 58 and releasing the latch 50 so that it will hook onto the lever and connect the arm 40 With the lever, as indicated in Figure 3. Now the cam 58, the position of which circumferentially of the shaft is controlled by the governor arms 72, acts on the lever 4.8 to apply the brake 84 and to bring the stop 3G into the path of the stop 38. The interval during which the brake is applied Will depend upon the position of the cam 58 which, in turn, depends upon the speed of the shaft at the time when the stop mechanism is thrown into operation and the shaft will be brought to rest uniformly Whatever its speed.l

While the invention has been shown and described as embodied in a mechanism iu which the speed reducing means is in the form of a friction brake, it will be understood that this construction is not essential to the broader features of the invention, and that so far as certain features of the invention are concerned the speed reducing' means may be of any suitable form, and that under eert-ain conditions the resistance of the moving parts may act as the speed reducing means. f

Having explained the nature and object of the invention, and specifically described one form of mechanism in which it may be embodied, what is claimed is rf 1. A stop mechanism having, in combination, means tor gradually retarding the driven parts until they come substantially to stopping position, and mechanism for regulating the retarding means by the speed of the driven parts to vary its retarding effect in accordance with the speed at the time the retarding means is rendered active.

2. A stop mechanism having, in combination, means for gradually retarding the drifven parts until they come substantially to stopping position, and mechanism for varying the duration of the retarding interval in accordance with the speed of the driven parts at the time the retarding means is rendered active.

3. A stop mechanism, having, in combination, means for reducing the speed of the driven parts substantially to stopping position, and means for varying the point in the movement of the driven parts at which the speed reduction begins in accordance with the speed of the driven parts at the time the stopping is to be effected.

4. A stop mechanism having, in combination, speed reducing means rendered active in stopping` the driven parts, and means for regulating the point in the movement of the driven parts at which the speed reduction begins by the speed of the driven parts at the time they are to be stopped.

A stop mechanism, having, in combination, a driven shaft, means for reducing the speed of the shaft prior to stopping it, and means for varying'the point in the rotation of the shaft `at Which the speed reduction begins in accorda-nce With the speed of the shaft at the time the stopping is to loe effected.

6. A stop mechanism` having, in combination, a brake for reducing the speed of the driven parte, and means for varying the point in the movement of the driven parts at which the brake is applied in accordance with the speed of the driven parts.

7. A. stop mechanism, having, in combination, means for retarding the driven parts as they come to stopping position, a cam, moving in unison with the driven parts for irritating the retarding action, and a centri fugal governor fc" controlling the cam to vary the retarding interval in accordance with the speed of the driven parts at the time the cam hecomes active.

S. fr stop mechanism., having, in comhination, means acting' when the power is thrown ofi' to retard the driven parts as they come to stopping position7 a cam for rendering' the retardirng` means active, and a centrifugal governor for (':ontrolling the timing of the cam.

.3l stop mechanism having, in combination. a brake for reducing' the speed of the driven parts, a cam moving in unison with the driven parts for applying' the hralie, and a centrifugal governor for regulating the point in the movement of the driven part at which the cam applies the hrale.

l0. A stop mechanism, having, in comhination, driving` mechanism for drivingl and for varying the speed of the driven parts.I normally inactive mechanism for continuously reducing the speed of the driven parts until they come substantially to stopping position, and means for varying the speed reducing interval preceding the final stopping in accordance with the speed of the driven parts,

ll. A stop mechanism, having, in combi nation. treadle controlled mechanism for driving and for varying the speed of the driven parts, mechanism for' continuously reducing the speed of the driven parts until they come substantially to stoppingl posi tion rendered active in throwing out the driving mechanism, and means for varying the speed reducing interval preceding the final stopping' in accordance With the speed of the driven parts.

l2. ifi stop mechanism, having, in comhination, a driven shaft, a cam mounted to turn on the shaft7 a centrifugal governor connected with the cam to determine its position on the shaft, and speed reducing and stopping mechanism controlled hy the cam.

13. A. stop mechanism, having,1 in comhination, a driven shaft, a cam mounted to turn on the shaft, a centrifugal governor connected with the cam to determine its position on' the shaft7 a lever arranged to he operated hy the cam, a brake shoe carrier, a latch link for connecting` the lever and carrier, and a power controlling` lever provided with means for disengaging the link and holding the lever out of the path of the cam.

1,5 :ii/,eve

lll. A stop mechanism, having, in c hination, a driven shaft, speed reduclngmeans, a controller cam mounted te tuin on the shaft for applying the speed reduci'm means, a centrifugal governor connected to the cam to determine its position circunn ferentially of the shaft, and means for loc; ing the cam in position on the shaft While active.

l5. A stop mechanism, having, in comhination, a driven shaft, s )eed reducing means, a cam for applying said means mounted turn on the shaft and having a limited radial movement, a paivl on the calm and teeth on the shaft cooperating' vvitl'i the paivi vto loci; the cam (hiring its action on the speed reducing means.

16. A stop mechanism, having, in combination, treadle controlled mechanism for driving and for varying Vthe speed of the driven parts, means rendered active in throwing out the driving mechanism for continuously retarding the parts until tief.' come to stopping` position. and mechanism for varying the retarding effect of said means in accordance vvith the speed of the driven parts at the time the driving' mechanism is thrown out.

17. A. stop mechanism, having, in comhination, driving mechanism. normally inf active and continuously acting speed reducing means for bringing the driven parts to substantially a state of rest rendered active when the driving mechanism is thrown out, and a centrifugal governor for varying the retardin` effe-ct of the speed reducing means in accordance with. the speed of the driven parts.

18. i stop mechanism, having, in comoi nation, driving` mechanism, a brake for reducing' the speed of the driven parts, mechanism for applying the loralie when the driving mechanism is thrown out including ay centrifugal governor for varying the hraling action of the lorake .in accordance With the speed of the driven parts.

19. .il stop mechanism, having, in cor-ahination, mechanism for continuously wt rding the driven parts when rendered acti ve, and mechanism for automaticallyv varying the retarding effect of such mechanism in accordance with the speed of the driven parte to bring them substantially to a state of rest at a predetermined point regardless o the speed at the time the stopping is to he effected.

LAURENCE E. TOPHAltl. 

